KR101087288B1 - Circular polarized antenna using satellite communication - Google Patents

Abstract

By using a feeding method using a dielectric insert waveguide and providing a small waveguide type antenna that can be integrated into a single dielectric substrate, it minimizes feeding loss in the high frequency band of satellite communication and integrates a circular polarization characteristic and an impedance matching network. Disclosed is a circularly polarized antenna for satellite communication having a wide bandwidth of impedance bandwidth.

The disclosed circular polarization antenna for satellite communication includes a dielectric substrate having a first array via in the form of a cylindrical cavity; A microstrip circular patch antenna located at the center of the cylindrical cavity and formed on the dielectric substrate to emit a signal; Feeding the signal to the microstrip circular patch antenna and implementing a circular polarization antenna for satellite communication, including a spherical dielectric embedded waveguide having a second array via, thereby implementing the impedance of the microstrip antenna formed on the substrate and the dielectric embedded waveguide It solves the impedance mismatch of the feeding structure and improves the impedance bandwidth of the antenna.

Cylindrical cavity, microstrip antenna, array via, dielectric insert waveguide

Description

Circular polarized antenna using satellite communication

The present invention relates to a circular polarization antenna for satellite communication, and more particularly, by using a power feeding method using a dielectric insert waveguide, and providing a small waveguide type antenna that can be integrated into a single dielectric substrate, The present invention relates to a circular polarization antenna for satellite communication which minimizes power supply loss and has a circular input polarization characteristic and an impedance matching network having a wide input impedance bandwidth.

Antennas mounted on satellites require stable gain characteristics, circular polarization characteristics, and beam widths, and must have strong thermal resistance to exhibit stable characteristics in space environments. It should be designed to be firm and light.

In addition, it is important to minimize the line loss in the feeding network of the antenna used in the X-band (8 ~ 12GHz) or more frequency band.

For feed networks used for microstrip single patch antennas and array antennas, microstrip or strip lines that can be implemented on dielectric substrates have been used. For satellite-mounted antennas that strictly require low loss specifications, the use of metal waveguides instead of the microstrip or strip lines can maximize energy transfer efficiency. However, metal waveguides have a disadvantage in that they are heavy and bulky.

The via array structure allows for the implementation of a Substrate Integrated Waveguide (SIW) that can be integrated into a dielectric substrate by creating a metal wall. The use of waveguides integrated on dielectric substrates allows for low wave loss and low weight waveguides.

Impedance matching networks are necessary to resolve the impedance mismatch between the cylindrical cavity-typed microstrip patch antenna and the dielectric interleaved waveguide feed structure to ensure minimal return loss.

Regarding the implementation of a spherical or cylindrical cavity type radiator using the via array structure as described above [Guo Quing Luo, Planar slot antenna backed by substrate integrated waveguide cavity ”, IEEE Antennas and Wireless Propagation Letters, vol . 7, 2008], Paper [Guo Qing Luo, “Single probe fed cavity backed circularly polarized antenna”, Microwave and Optical Technology Letters, vol. 50, no. 11, November, 2008, respectively.

Guo Quing Luo, “Planar slot antenna backed by substrate integrated waveguide cavity”, IEEE Antennas and Wireless Propagation Letters, vol. 7, 2008] is an antenna using a slot slot for linear polarization, and it is difficult to prevent radiation loss from the track by using microstrip line feeding. In addition, there is a problem in that the impedance bandwidth characteristics of the narrow band because there is no impedance matching structure.

Guo Qing Luo, “Single probe fed cavity backed circularly polarized antenna”, Microwave and Optical Technology Letters, vol. 50, no. 11, November, 2008] has implemented a cross slot for the purpose of circular polarization, and the probe feeding method using the SMA connector was selected. A via arrangement for implementing a cylindrical cavity shape is shielded in all spaces, which makes it impossible to implement an array antenna using multiple feeds. In addition, as in the case of the above paper, the absence of an impedance matching network has a narrowband characteristic of 3.2% based on the -10dB impedance bandwidth, making it difficult to use for X-band satellite communication requiring a bandwidth of 400 MHz or more.

Accordingly, the present invention has been proposed to solve various problems occurring in the conventional communication antenna as described above.

SUMMARY OF THE INVENTION An object of the present invention is to provide a small waveguide type antenna that can be integrated into a single dielectric substrate using a power feeding method using a dielectric insert waveguide.

Another object of the present invention is to provide a circular polarization antenna for satellite communication having a broadband impedance bandwidth by minimizing power supply loss in a high frequency band of satellite communication and integrating a circular polarization characteristic and an impedance matching network.

Another problem to be solved by the present invention is to improve the gain and efficiency of the conventional microstrip circularly polarized antenna, and to arrange the vias on a single dielectric substrate to form a cylindrical cavity structure, thereby minimizing and reducing the overall antenna volume and optimally To provide a circularly polarized antenna for satellite communications.

According to the present invention for solving the problems as described above "satellite communication circular polarized antenna",

A dielectric substrate on which first array vias of a cylindrical cavity structure are formed;

A microstrip circular patch antenna located at the center of the cylindrical cavity structure and formed on the dielectric substrate to emit a signal;

And a spherical dielectric embedded waveguide for feeding the signal to the microstrip circular patch antenna.

The spherical dielectric internally inserted waveguide is formed on the dielectric substrate.

In addition, the circular polarization antenna for satellite communication,

And an etch pattern and a third array via to form an impedance matching network for impedance matching between the spherical dielectric embedded waveguide and the microstrip circular patch antenna.

In addition, the circular polarization antenna for satellite communication,

A microstrip line formed on the upper plate positioned above the dielectric substrate to receive a signal;

The second array via is horizontally formed on the microstrip line to the left and right of the microstrip line.

In addition, the third array via is formed perpendicular to the second array via, characterized in that formed in only one direction of the left or right of the microstrip line.

The upper plate may further include a signal transition unit connected to one end of the microstrip line to transfer an incoming signal to the dielectric insertion waveguide.

In addition, the microstrip circular patch antenna has a slot formed at a specific position in order to form two electric fields having a phase difference of 90 ° with the same size, and the width component W1 forming the area and the area of the slot. , The center frequency and purity of the axial ratio are adjusted according to the length ratio between the vertical length components W2.

According to the present invention, there is an advantage of designing a single element antenna that can be used for a satellite array antenna for high-speed data communication based on stable gain characteristics and circular polarization characteristics.

According to the present invention, since a small circular polarization generating antenna can be integrated on a single substrate, it is possible to reduce the weight and can be implemented as a planar antenna having a simple structure as compared to other antennas having a large number of structural combinations. There is an advantage in providing a circular polarized antenna for satellite communication in a form suitable for the strong and space environment.

According to the present invention, there is an advantage of providing broadband antenna characteristics by solving the narrow band antenna characteristics caused by the low thickness of the dielectric substrate by using an impedance matching network that can be integrated therein.

According to the present invention, it is possible to secure stable excellent circular polarization characteristics of a circular microstrip patch antenna to which a slot (Slot or Perturbation) is applied, and to change the position of the via array constituting the impedance matching network including the slot rotation. To right), it is easy to convert to an antenna exhibiting left-hand circular polarization (LHCP) characteristics.

Hereinafter, described in detail with reference to the accompanying drawings a preferred embodiment of the present invention. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

In adding reference numerals to the components of each drawing, it should be noted that the same components as much as possible, even if displayed on different drawings. Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

Figure 1a is a three-dimensional exploded perspective view of the antenna of the present invention, in particular, a circular polarized antenna for satellite communication in the form of a circular cavity that can be integrated into a dielectric substrate operating in the X-band.

As shown in FIG. 1A, the satellite communication circularly polarized antenna integrated in a dielectric substrate having a cylindrical cavity type according to the present invention includes a dielectric substrate 5, a top plate 1 formed on the dielectric substrate 5, and The lower plate 10 is formed below the dielectric substrate 5.

The dielectric substrate 5 is formed with a cylindrical cavity structure formed by the first array vias 7, and a microstrip circular patch antenna 2 for signal radiation is provided at the center of the cylindrical cavity structure. Here, the cylindrical cavity structure and the microstrip circular patty antenna 2 serve as radiators.

In addition, the dielectric substrate 5 is formed with a spherical dielectric embedded waveguide 12 formed by a second array via 9 and an impedance between the spherical dielectric embedded waveguide 12 and the microstrip circular patch antenna 2. An upper plate etching pattern 3 and a third array via 8 are formed as an impedance matching network for matching the circuits. Here, the spherical dielectric internally inserted waveguide 12, the top plate etching pattern 3, and the third arrayed vias 8 serve as power feeds.

In addition, a third array via 8 is formed in the dielectric substrate 5 to be perpendicular to the second array via 9, which is arranged on the left side of the dielectric embedded waveguide 12. Or it is formed only in one direction of the right side. In the present invention, preferably formed on the left side of the dielectric inserting waveguide 12 on the basis of the plan view shown in FIG.

FIG. 1B is a view showing a combination of a microstrip line 4 and a signal transition portion 11 for feeding a signal between the microstrip line 4 and a dielectric insertion waveguide 12 to measure the characteristics of FIG. 1A. It is shown.

1C is a side view and a plan view of FIG. 1B. The dielectric substrate 5 having a predetermined thickness h and the upper plate 1 and the lower plate 10, which are metal plates, have a single substrate form.

Two slots 13 are formed in the microstrip circular patch antenna 2, and the microstrip circular patch antenna 2 is designed to generate even circular polarization (RHCP) by the two slots 13 formed in this way. The probe via 6 having a diameter of 0.3 mm electrically shorts the microstrip circular patch antenna 2 and the lower plate 10. The position of the probe via 6 affects the impedance matching and the center frequency and purity of the axial ratio can be determined according to the degree of rotation about the center of the microstrip circular patch antenna 2.

In addition, the antenna axis ratio of the present invention is that the slot 13 is formed at any position in order to form two electric fields having a phase difference of 90 ° with each other of the same size, mainly in the microstrip circular patch antenna (2). The ratio is determined by the two slots 13. That is, the center frequency and purity of the axis ratio can be adjusted according to the length ratio between the width component W1 and the length component W2 forming the area and the area of the slot 13.

The first array via 7 implementing the cylindrical cavity structure and the second array via 9 implementing the spherical dielectric internal waveguide 12 are electrically shorted by connecting the top plate 1 and the bottom plate 10. It is designed to recognize a metal wall for waves traveling inwards. The diameter v1 of the vias applied to the first and second array vias 7 and 9 and the spacing d1 between the vias are all equal to 1 mm and 1.5 mm, which results in a frequency having a wavelength of approximately 30 mm. GHz) is designed to be recognized as a flat metal wall.

FIG. 2 is an enlarged detailed plan view of the impedance matching network of FIG. 1C. The impedance matching network is integrated inside the spherical dielectric embedded waveguide 12. The feeding structure of the spherical dielectric inner waveguide 12 fixed the width (a ₁ ) to 16 mm according to standard waveguide design criteria to operate at 10 GHz, the center frequency of the X-band. Recommended frequency band at this time is 8.2 ~ 12.4GHz, TE10 The cut-off frequency for the fundamental mode is 6.3 GHz, and waves cannot travel for the following frequency bands.

In addition, the impedance matching network of FIG. 2 is composed of an etching pattern 3 and a third array via 8 on the upper plate 1. In the case of the etching pattern 3, it is determined by the combination of the variables h ₁ , h ₃ and a ₄ , and in the case of the third array via 8, it is determined by the combination of the variables d ₂ , h ₂ and v ₂ , including the number of vias. do. The detailed role of each variable will be described in detail later with reference to FIGS. 4A to 4C and 5A to 5D.

FIG. 3 shows a simulation comparison result of impedance bandwidth change with or without the third array via 8 in the impedance matching network. Based on the return loss of -10dB and -14dB, the degree of impedance matching is clearly shown with or without the third array via 8.

FIG. 4A is a graph for showing simulation results for the change of the transverse component a ₄ of the etching pattern 3 forming the impedance matching network. The change in the transverse component of the pattern mainly affects the impedance matching to the resonance generated at 9.7 GHz, and has little effect on the changes in the impedance bandwidths of -10 dB and -14 dB. That is, it can be used as a useful variable that can have a stable return loss characteristic by obtaining an optimal pattern transverse component value within a corresponding frequency band.

FIG. 4B is a graph for showing simulation results for the change in the longitudinal component h ₃ of the etching pattern 3 forming the impedance matching network. It can be seen that the change in the -14dB impedance bandwidth is noticeable according to the value of this variable.

FIG. 4C is a graph for showing simulation results for the change in the total length component h1 of the etching pattern 3 forming the impedance matching network. The feeding structure of the dielectric interleaved waveguide 12 should guide the wave as close as possible to the patch antenna in order to deliver maximum energy to the microstrip circular patch antenna 2 with minimal return loss. However, when the total length of the etching pattern 3 is too long to approach the microstrip circular patch antenna 2, the coupling phenomenon between the metals is intensified and the impedance of the microstrip circular patch antenna 2 is changed. This can be confirmed from this graph. As the length of h ₁ is secured up to 9.57mm, it shows stable impedance matching characteristic, so it is possible to secure the bandwidth of -14dB, but the microstrip circular patch antenna (2 If too close to), the impedance bandwidth narrows. Therefore, it is preferable to effectively set the length of the etching pattern 3 through experiment.

The third array via 8, which forms the impedance matching network, includes the basic mode of the microstrip circular patch antenna 2 in TE10 mode, which serves as the impedance matching network, as well as the basic mode of the spherical dielectric embedded waveguide 12 feeding structure. It acts as a transformer for the mode.

As noted in FIG. 2, the third arrangement via 8 is composed of the number of vias and the position variables h ₂ and d ₂ , and the via diameter variable v ₂ .

FIG. 5A is a graph for illustrating a return loss simulation result for a change in the number of vias of array vias forming an impedance matching network. FIG. The diameter of the via (v ₂ ) is 0.3 mm, and the number of vias varies from 5 to 8 with the gap between the vias fixed at 0.7 mm. As the vias are arranged from five to seven, the return loss stabilizes to -14dB. In addition, increasing the number of vias to eight shows that the frequency distance between the two resonances begins to increase and no longer satisfies the -14 dB criterion with a standing wave ratio (VSWR) of 1.5: 1.

FIG. 5B is a graph for showing a return loss simulation result for the variation of the via spacing d ₂ of the third array via 8 forming the impedance matching network. As the spacing between vias changes, the degree of capacitive coupling formed between vias changes, which affects the impedance change. In addition, increasing the via spacing beyond a certain level narrows the path through which waves can pass, reflecting large amounts of power and increasing return loss. The graph shows that the impedance matching improves as the spacing increases from 0.4mm to 0.6mm, and above 0.8mm, the distance between the two resonances is far enough to satisfy the -14dB impedance bandwidth. In addition, when d ₂ = 1 mm, it can be seen that the third array via 8 of the impedance network acts as if it is a metal wall, so that a large amount of power is reflected and reflection loss increases. That is, it is preferable to satisfy the optimum impedance matching condition by appropriately changing d ₂ , which is an interval between vias.

FIG. 5C is a graph for showing a return loss simulation result for a change in the position variable h ₂ of the third array via 8 forming an impedance matching network. The position variable h ₂ moves with respect to the signal transition unit 11 and may be positioned within a structure within a range of 0 to 7.8 mm. From the graph results, h ₂ shows the maximum impedance matching characteristic within the range of 6.6 ~ 7.2mm, and does not satisfy the impedance bandwidth in the other position range.

FIG. 5D is a graph for showing a return loss simulation result for the change in the via diameter size variable v ₂ of the third array via 8 forming the impedance matching network. This simulation aims to compare the characteristics result considering the diameter of the available vias. As a result, when the via diameter between 0.3 and 0.6 mm is selected, the resonance frequency is insignificant but the impedance bandwidth within -14 dB can be satisfied. Therefore, it may be changed in consideration of the production environment.

FIG. 6 is a graph showing simulation and measurement results for return loss of a finally designed antenna obtained through an optimization process of antenna parameters. The two results show a generally consistent characteristic. The measured return loss is 8.82 ~ 11.16GHz based on the standing wave ratio of 2: 1 (-10dB), and has a broadband characteristic with an impedance bandwidth of 2.34 GHz (23.42%), and the standing wave which is a requirement of the antenna used for satellite communication. Ratio 1.5: 1 (-14dB) based on 9 ~ 10.4GHz, the impedance bandwidth is 1.4GHz (14.43%).

The satellite communication circularly polarized antenna integrated in the cylindrical cavity-type dielectric substrate proposed by the present invention overcomes the short-band impedance bandwidth disadvantage of the conventional microstrip patch antenna. This is due to the optimal mode conversion characteristics by the impedance matching network integrated inside the feed structure of the dielectric interleaved waveguide 12.

7 is a graph for comparing simulation and measurement results, respectively, for the gain and axial ratio characteristics of the present invention. It can be seen that the gain and axial ratio characteristics are consistent with the simulation results and the measurement results, and stable antenna characteristics can be expected through the optimization process of the antenna parameters.

Gain characteristics of the present invention is 4.8 to 7.5 dBi from 8.9 to 10.9 GHz, showing a uniform change within the range of 3 dBi to ensure a stable characteristic.

The excellent circular polarization (RHCP) axial ratio characteristic of the present invention shows the maximum purity characteristic at 10.3 GHz and can be expected to be almost the same as the simulation.

8 is a graph for showing a measurement result for the radiation pattern characteristics of the present invention. Referring to the coordinate axes shown in FIG. 1C, the superior circular polarization (RHCP) and left-hand circular polarization (LHCP) characteristics for the yz and zx planes of the antenna of the present invention are presented. The measurement frequency is 10.3 GHz and the superior circular polarization characteristic is superior in all planes. In particular, the excellent circular polarization-to-left circular polarization ratio of the z-axis (θ = 0 °) in the zx plane (Φ = 0 °, 0 ° ≤ θ ≤ 360 °) is 15dB. It was confirmed that the show.

The present invention is not limited to the above-described specific preferred embodiments, and various modifications can be made by any person having ordinary skill in the art without departing from the gist of the present invention claimed in the claims. Of course, such changes will fall within the scope of the claims.

1A is a three-dimensional exploded perspective view of a circularly integrated circularly polarized wave generating antenna and impedance matching structure according to the present invention;

FIG. 1B is a three-dimensional exploded perspective view combining a microstrip line and a microstrip to dielectric interleaved waveguide transition structure to measure the properties of FIG. 1A; FIG.

1C is a plan view and a side view of FIG. 1B.

FIG. 2 is a detailed plan view of a network for impedance matching consisting of array vias and etching patterns present within the dielectric interleaved waveguide of FIG. 1B; FIG.

3 is a graph of return loss with and without array vias for impedance matching;

FIG. 4A is a graph for comparing simulation results of impedance matching changes with changes in transverse component (a ₄ ) of an etching pattern forming an impedance matching network. FIG.

FIG. 4B is a graph for comparing simulation results of impedance matching change with the change of the longitudinal component (h ₃ ) of the etching pattern forming the impedance matching network. FIG.

FIG. 4C is a graph for comparing simulation results of impedance matching changes with changes in the overall length component h ₁ of the etching pattern forming the impedance matching network. FIG.

5A is a graph for comparing simulation results of changes in impedance matching according to changes in the number of vias constituting the impedance matching network.

FIG. 5B is a graph for comparing simulation results of impedance matching change according to a change in interval d ₂ between vias constituting the impedance matching network. FIG.

FIG. 5C is a graph for comparing simulation results of impedance matching changes according to changes in positional variables h ₂ of array vias constituting an impedance matching network. FIG.

FIG. 5D is a graph for comparing simulation results of impedance matching change according to change in diameter variable (v ₂ ) of array vias constituting the impedance matching network. FIG.

6 is a graph for explaining a result of measuring the return loss of FIG. 1B.

FIG. 7 is a graph for explaining a result of measuring gain and axis ratio of FIG. 1B; FIG.

8 is a graph for explaining the result of measuring the radiation pattern of FIG.

<Explanation of symbols for the main parts of the drawings>

One… Tops

2… Microstrip Circular Patch Antenna

3 ... Etching pattern

4… Microstrip Track

5... Dielectric substrate

6... Probe via

7 ... First array via

8… 3rd array via

9... 2nd array via

10... Bottom plate

11... Signal transition

12... Insertion waveguide inside dielectric

13... slot

Claims (12)

In the circular polarization antenna for satellite communication, A dielectric substrate on which first array vias of a cylindrical cavity structure are formed; A microstrip circular patch antenna located at the center of the cylindrical cavity structure and formed on the dielectric substrate to emit a signal; And a spherical dielectric embedded waveguide for feeding the signal to the microstrip circular patch antenna. delete 2. The circular polarization antenna of claim 1, wherein the spherical dielectric internal waveguide is formed in the dielectric substrate. The method of claim 3, And a third array via and an etching pattern for forming an impedance matching network for impedance matching between the spherical dielectric internal waveguide and the microstrip circular patch antenna. delete delete delete The method of claim 4, wherein the third array via, It serves as an impedance matching network and at the same time serves as a transformer for converting from TE10 mode, which is the basic mode of the spherical dielectric insert waveguide feeding structure, to TM11 mode, which is the basic mode of the microstrip circular patch antenna. Circularly polarized antenna for satellite communications. 2. The circular polarization antenna for satellite communication according to claim 1, further comprising a signal transition portion for transmitting the signal to the dielectric insert waveguide. The method of claim 4, wherein the microstrip circular patch antenna, A circular polarized antenna for satellite communication, characterized in that a slot is formed to form two electric fields having a phase difference of 90 ° with each other of the same size. The method of claim 10, wherein the microstrip circular patch antenna, And a center frequency and purity of the axial ratio according to the length ratio between the area of the slot and the length component (W1) and the length component (W2) forming the area. The method of claim 11, wherein the microstrip circular patch antenna, A circular polarized antenna for satellite communication comprising a probe via for electrically shorting the lower plate.

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